Louis Oosthuizen saw his lead cut to just one shot as Branden Grace made a fast start in the final round of the South African Open hosted by the City of Johannesburg.
Oosthuizen entered Sunday at Randpark Golf Club with a three-shot lead but dropped two shots in his first three holes to slip back to 12 under.
Grace birdied four of his first six to get within one, with home favourites Jbe Kruger, Haydn Porteous and Charl Schwartzel, English pair Matt Wallace and Oliver Wilson and Zambia's Madalitso Muthiya at nine under.
Wilson made a fast start with birdies on the third and fourth and when he hit an excellent approach into the sixth, he was up to nine under.
Grace birdied the first with a long putt but gave the shot straight back before making another gain from 15 feet at the third.
Schwartzel was the next man to join the group five off the lead but the did it the wrong way, going out of bounds off the tee at the second and making a double-bogey.
Oosthuizen recovered from a poor tee-shot on the first to make a par but Muthiya dropped a shot and roles were reversed on the second.
Another poor tee-shot from the leader this time led to a dropped shot, while Muthiya made a gutsy 15-footer to save par.
Wallace, meanwhile, found the hazard with his second and a double-bogey dropped him back to nine under.
Kruger had bogeyed the first but he took advantage of the par-five fourth and then holed a long putt on the fifth, while Porteous also made a move with birdies on the fifth and sixth.
Grace then broke out of that group at nine under with a 20-footer on the fifth.
A poor second shot from Muthiya saw him surrender a bogey on the third and with Oosthuizen going right off the tee and failing to get up and down from the sand, the lead was down to two.
Grace hit a stunning approach to tap-in range on the sixth and he was all of a sudden just a shot back.
Ernie Els, Thomas Aiken, Robert Langasque, Robert MacIntyre and Adilson da Silva were then at eight under.